Alkaline activation of high-calcium ash and iron ore tailings and their recycling potential in building materials Ativação alcalina de cinzas com alto teor de cálcio e rejeito de minério de ferro e seu potencial de reciclagem para utilização como material de construção
Augusto Cesar da Silva Bezerra Sâmara França Luciano Fernandes de Magalhães Maria Cristina Ramos de Carvalho Abstract lkali-activated materials are agglomerates obtained from the alkaline activation of aluminum- and silicone-rich precursors. The most popular precursors for this type of activation are low-calcium fly A ashes, blast furnace slag, and metakaolin. However, both high-calcium ashes (HCAs) and iron ore tailings (IOTs) are interesting wastes that can be investigated as precursors because of their available volume and environmental impact during their final deposition. Therefore, by performing tests of compressive strength, FTIR spectrometry and scanning electron microscopy, we sought to identify the products formed during HCA and IOT activation without thermal treatment. Nine mortar formulations with different HCA and IOT proportions were developed using sodium hydroxide and sodium silicate as activators. Thus, using FTIR spectrometry, we observed the reaction between the industrial wastes. Additionally, the compressive strength result suggested that the material could be used as compressed blocks in masonry walls for the development of more environmentally friendly building materials, which would mitigate the impact of waste disposal and convert industrial solid waste into value-added products. Keywords: Alkaline activation. High-calcium ash. Iron ore tailings. Compressed blocks. Waste valorization. ¹Augusto Cesar da Silva Bezerra ¹Centro Federal de Educação Tecnológica de Minas Gerais Resumo Belo Horizonte – MG – Brasil Materiais álcali ativados são aglomerantes obtidos a partir da ativação alcalina de precursores ricos em alumínio e silício. Os precursores mais comuns utilizados ²Sâmara França ²Centro Federal de Educação para ativação são as cinzas com baixo teor de cálcio, as escórias de alto forno e o Tecnológica de Minas Gerais metacaulim. Contudo, a cinza de cavaco de eucalipto (CCE) e o rejeito de minério Belo Horizonte – MG – Brasil de ferro (RMF) são resíduos interessantes para ser estudados como precursores
devidoao volume disponível e ao impacto ambiental advindo de sua deposição ³Luciano Fernandes de final. Diante disso, por meio de ensaios de resistência à compressão, Magalhães espectrometria de FTIR e microscopia eletrônica de varredura buscou-se ³Centro Federal de Educação identificar os produtos formados pela ativação alcalina da CCE e RMF. Para isso Tecnológica de Minas Gerais Belo Horizonte – MG – Brasil foram desenvolvidas nove pastas com proporções diferentes de CCE e RMF, utilizando como ativadores o hidróxido de sódio e o silicato de sódio. Como
4 resultado observou-se pela espectrometria FTIR a reação entre os resíduos Maria Cristina Ramos de industriais. A resistência à compressão sugere que o material álcali ativado pode Carvalho 4Centro Federal de Educação ser utilizado como blocos compactados para a alvenaria de vedação, de forma a Tecnológica de Minas Gerais contribuir para o desenvolvimento de materiais mais ecológicos, mitigando os Belo Horizonte – MG – Brasil impactos ambientais causados pela disposição e transformando os resíduos
sólidos industriais em produtos com valor agregado. Recebido em 24/06/18 Palavras-chave: Ativação alcalina. Cinzas com alto teor de cálcio. Rejeito de minério Aceito em 28/10/18 de ferro. Blocos compactados. Reciclagem.
BEZERRA, A. C. S.; FRANÇA, S.; MAGALHÃES, L. F.; CARVALHO, M. C. R. Alkaline activation of high-calcium ash 99 and iron ore tailings and their recycling potential in building materials. Ambiente Construído, Porto Alegre, v. 19, n. 3, p. 99-112, jul./set. 2019. ISSN 1678-8621 Associação Nacional de Tecnologia do Ambiente Construído. http://dx.doi.org/10.1590/s1678-86212019000300327 Ambiente Construído, Porto Alegre, v. 19, n. 3, p. 99-112, jul./set. 2019.
Introduction Alkali-activated materials are potential substitutes According to the work by Amaya et al. (2015), for Portland cement because of their mechanical when burning charcoal, approximately 1 % of the properties, durability, and low environmental material is transformed into ash. Thus, in the 20 impact and because they do not emit CO2 during million eucalyptus hectares planted, it is estimated their production. (PACHECO-TORGAL; that approximately 74x105 t of ash are produced, CASTRO-GOMES; JALALI, 2008; PROVIS, according to the average Brazilian productivity 2018). Such binders are obtained via the level; however, the productivity may vary polymerization of aluminum- and silicone-rich according to the type of soil, climate and spacing precursors that are dissolved in highly alkaline between plants (INDÚSTRIA…, 2017). solutions (YIP; LUKEY; VAN DEVENTER, High-calcium ashes from eucalyptus have already 2005; FOUCHAL et al., 2015). been proven to be viable cementitious materials Several authors have stated that alkaline activation that can replace Portland cement in proportions up products depend on the precursors and activators to 15 % (RESENDE et al., 2014). It is believed used (ISMAIL et al., 2014; PROVIS; BERNAL, that above this replacement content the ash will not 2014). Thus, the variability and complexity of the behave similar to other ashes, such as sugar cane resulting products are still a challenge for bagasse or rice husk ashes, because of its low researchers (MYERS et al., 2015; PROVIS; silicon oxide content (PARIS et al., 2016; PALOMO; SHI, 2015). According to Provis et al. BEZERRA et al., 2017). (2015), high-calcium precursors produce calcium Although wood is a renewable energy source and aluminosilicate hydrate (C-A-S-H) with a aids in capturing carbon, 70 % of wood ash is tobermorite-like structure as the main usually disposed of in landfills (CHOWDHURY; geopolymerization product, whereas precursors MISHRA; SUGANYA, 2015). Ashes treated as with a low calcium content are more likely to form waste increase the landfill rate and impose costs on aluminosilicate alkalis (N-A-S-H) that have a high the incinerator, which often renders biomass-based crosslinking density. These geopolymerization energy production as economically unfeasible products are directly related to the mechanical (OBURGER et al., 2016). Moreover, wood ashes resistance of the alkali-activated material have a high alkalinity, and depending on the extent (PUERTAS et al., 2011; REDDEN; of changes in the soil solution chemistry, NEITHALATH, 2014). According to Redden and pronounced changes in soil pH may also have an Neithalath (2014), higher alkali concentrations in undesirable effect that leads to increased leaching an activator increases the generation of N-A-S-H. of pollutants and nutrients. Additionally, some of Puertas et al. (2011) concluded that C-A-S-H the inorganic compounds could become toxic at formed from NaOH presents a structure similar to high concentrations (WIKLUND, 2017). Thus, the C-S-H with tobermorite and chain lengths between EPC (EUROPEAN…, 2002) waste framework 5 and 14. When the activator is sodium silicate, (Decision 1666/2002/EC) has set up a hierarchy of tobermorite with chain lengths of 11 and 14 also waste treatment options, preferring prevention, exists. reuse and recycling over disposal. The main reports on this subject have studied low- IOTs can also be used as a precursor, and it is a calcium fly ash, iron ore tailings (IOTs), and waste that is generated by the mining sector metakaolin as precursors for alkali-activated (BASTOS et al., 2016). Global iron ore production materials (PROVIS; BERNAL, 2014). However, is 2,230 billion metric tons (Gt) of usable ore and high-calcium ashes (HCAs) for use as eucalyptus 1,360 billion metric tons of iron content. Global chip ashes appear to be an interesting waste for iron ore production in 2016 on a usable-ore basis investigation because of their volume and chemical was led by the countries listed in Table 1, which composition. According to Myburg et al. (2014) together accounted for 93.59 % of global and Larcombe et al. (2015), eucalyptus is the most production (U.S. GEOLOGICAL…, 2017). cultivated wood in the world (i.e., the main reforestation wood) with approximately 20 million Based on data from global iron ore production hectares planted in more than 100 countries across (U.S. GEOLOGICAL…, 2017) and the generation six continents. However, the steel industry of IOTs in China in 2010 (MENG; NI; ZHANG, demands large volumes of charcoal and due to 2011), it is estimated that 3,360 billion metric tons social and environmental aspects, it uses of IOTs were generated in 2014 around the world. reforestation wood for production (GONÇALVES et al., 2014).
100 Bezerra, A. C. S.; França, S.; Magalhães, L. F.; Carvalho, M. C. R. Ambiente Construído, Porto Alegre, v. 19, n. 3, p. 99-112, jul./set. 2019.
Table 1 – Iron ore production in 2016 Country Production (Gt) Australia 825 Brazil 391 China 353 India 160 Russia 100 South Africa 60 Ukraine 58 Canada 48 United States 41 Iran 26 Sweden 25
IOTs are usually disposed of as a dam (BASTOS China due to the billions of tons generated there. et al., 2016; PAPPU; SAXENA; ASOLEKAR, Additionally, in Australia, Kuranchie et al. (2015) 2007). Dams have a high implementation impact studied IOTs as aggregates in concrete. due to their high volume and may cause Thus, this study aimed to understand the chemical environmental and social impacts when disruption interactions to produce scientific knowledge that occurs (PASSOS; COELHO; DIAS, 2017). Thus, could reduce the impact of deposition of these the safety of tailing dams is currently a challenge industrial wastes in the future by incorporating for engineering. Dams are designed to last them into building materials. Thus, the products indefinitely; however, in recent decades, accidents formed from the activation of the two wastes have occurred that have devastated the surrounding without thermal treatment were identified, IOTs ecosystem and victimized hundreds of species and HCAs, and we correlated them with the (AIRES et al., 2018). In 1998, a dam failure in compressive strength obtained from using different Aznalcollar, Spain released 2 million m³ of toxic proportions. The phases were identified using mud into the environment, resulting in the FTIR spectrometry and scanning electron contamination of aquifers and surface water and microscopy. the death of several aquatic species (DAVIES, 2002). In 2003, a major disaster of this type occurred in the Republic of Macedonia, releasing Materials and methods 100,000 m³ of damaging tailings with heavy IOT samples were collected from the pulp filter at metals in the Kamenica River. The height of the the end of the beneficiation process of iron ore. tailing flow was approximately 10 meters and the The HCA sample was obtained at the bag filter of length was 12 km (VRHOVNIK et al., 2013). boilers used for steam production. The tailings and Additionally, mine tailings are generally linked to ashes endured a milling process in the Pulverisette elevated heavy metals (JUWARKAR; 5 planetary mill, Fritsch, at 300 rpm for 10 min. JAMBHULKAR, 2008), a lack of organic matter After milling, the particle size distribution of the and nutrients (LANGE et al., 2012), an acidic pH tailings and ashes were determined using a laser (CHATURVEDI; AHMED; DHAL, 2014), a poor granulometer, the Cilas 1090 laser particle size water holding capacity (MOUAZEN et al., 2014), analyzer. a high bulk density (SAKAI et al., 2008) and a The chemical compositions of IOTs and HCAs high salinity (LI et al., 2014). were determined via a casting method using Because of the impact of its deposition, some lithium tetraborate in X-ray fluorescence authors have already studied the reuse of IOT. spectrometers (PANalytical and Axios Fast and Zhang, Ahmaris and Zhang (2011) showed that Axios models, respectively). The mineralogical IOTs are a promising construction material if composition was determined via X-ray diffraction utilized with geopolymerization technology. using an XRD-7000 instrument from Shimadzu at Bastos et al. (2016) also investigated the potential 40 kV and 30 mA using Cu radiation. The angular of IOTs for infrastructure materials when properly speed was 0.24°/min, and the scan interval was stabilized. Recently, concretes and mortars with from 2θ = 5° to 80°. To analyze the diffractogram, IOTs were investigated (CARRASCO et al., 2017; the demonstrative version of the Match! software SANTANA FILHO, et al., 2017; FONTES et al., and the Crystallography Open Database, revision 2016; HUANG et al., 2013). Cui et al. (2017) 204654 from January 2018 was used. utilized IOTs for autoclaved aerated concrete in
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For specimen molding, Brazilian standard sand, HITACHI SEM, model TM 3000, with a back- NBR 7214 (ABNT, 2015), was used in medium- scattered electron detector. fine (# 50) and fine (# 100) particle sizes. As For statistical evaluation of the compressive activators, we used sodium silicate from Imperial strength results, we used the "Anova: Simple Química with a SiO2/Na2O = 2.15 ratio in solution factor" method using Microsoft Excel software and and 47.19 % of solids and 98 % pure solid sodium a significance level of 5 %. The results of the hydroxide. Additionally, all mixtures used the ANOVA were verified by the hypothesis that the superplasticizer additive, Silicon ns high 400, results of the compressive strength of the which is based on polycarboxylates modified with specimens are exactly equal in the gap, i.e., the stabilized nanosilica at a pH of 3.0±1.0, a specific results can be considered similar. For the analysis, mass of 1.09+0.02 g/cm³ and a chloride content of we took into consideration the source of variation < 0.15 % (SILICON, 2017). Despite the between groups and within groups. For the P value polycarboxylic-ether-based superplasticizer not test, P values smaller than the degree of being efficient for this type of material (LASKAR; significance rejected the equality between the BHATTACHARJEE, 2013), the plasticizer was resistors. Another method of analysis was to used because of its silica-containing chemical compare the value of the critical region boundary composition that was in the proportion of 2 % of (critical F) and the value of F (F). If "F" exceeded the precursors’ mass; the activator/precursor ratio "critical F", the hypothesis needed to be rejected. was 0.7. The mortars were developed from these materials as shown in Table 2. Four specimens for each proportion and age were molded, following Results the recommendations of NBR7215 and ASTM The chemical compositions of the IOTs and HCAs C109/C109 M (ABNT, 1996; AMERICAN…, obtained via XRD are shown in Table 4. As 2016) standards in cylindrical 25 x 50 mm shown, the main constituents of the IOTs are (diameter x height) PVC molds. Curing occurred Fe2O3 (65.78 %), SiO2 (22.3 %), and Al2O3 (4.25 at room temperature. The specimens were tested %). Other components appear in quantities below 1 for compression at 7 and 28 days using an EMIC %. HCA is chemically composed mostly of CaO universal testing machine at a 0.25 + 0.05 MPa/s (43.1 %), MgO (8.24 %), Al2O3 (4.94 %), K2O loading speed according to the testing (4.52 %), P2O5 (3.24 %), and Fe2O3 (2.42 %). The recommendations of the NBR7215 standard HCA showed a loss on ignition of 29.66 %, and (ABNT, 1996). Table 3 shows the amount of each much of this loss may be due to the high carbon activator used and the amount of water required to content of HCA. This loss on ignition is higher maintain the same activator/precursor ratio in all than that reported in the literature (PARIS et al., mixtures. To obtain insight into the 2016), and because the HCA is originated from physicochemical behavior of this system, FTIR biomass, it contributes even more to the capture was used to confirm the existence and formation of and removal of CO2 mentioned above (ZHAO, the phases during the geopolymerization phase. 2018; ROGELJ et al., 2016). The main minerals The infrared spectra were recorded using an IR- present in the IOTs and HCAs, as shown in Figure Prestige 21 from Shimadzu using the KBr method. 1, were identified in the diffractogram as showed For the morphological characterization, fragments in Table 5. of the broken specimen were imaged using a
Table 2 – Material Ratios HCA IOT Mortars SiO2/Na2O Activator/precursor Plasticizer (%) (%) HCA70 IOT30 SN1.00 70 30 HCA50 IOT50 SN1.00 50 50 1.00 HCA30 IOT70 SN1.00 30 70 HCA70 IOT30 SN1.55 70 30 2 % mass of HCA50 IOT50 SN1.55 50 50 1.55 0.7 precursors HCA30 IOT70 SN1.55 30 70 HCA70 IOT30 SN1.85 70 30 HCA50 IOT50 SN1.85 50 50 1.85 HCA30 IOT70 SN1.85 30 70
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Table 3 – Activator ratio
IOT+HCA SiO2Na2O Na(OH) Water Water/activator Activator/ SiO2/Na2O (g) (g) (g) (g) (g) precursor 1.00 10.00 2.25 43.75 3.57 1.55 80.00 18.12 1.37 36.51 1.87 0.70 1.85 21.00 0.67 34.33 1.58
Table 4 – Chemical composition
Material SiO2 Al2O3 Fe2O3 CaO MgO TiO2 Na2O K2O P2O5 MnO LOI IOT 22.30 4.25 65.78 0.01 0.14 0.21 <0.10 0.04 0.15 0.50 6.10 HCA 1.75 4.94 2.42 43.10 8.24 0.50 0.28 4.52 3.24 0.39 29.66
Figure 1 – Diffractogram of (a) IOTs and (b) HCA
(a) (b)
Table 5 – Chemical composition IOT HCA quartz (SiO2) (cod 9005019) calcite (CaCO3) (cod 1010962), hematite (Fe2O3) (cod 9000139) calcium oxide (CaO) (cod 1011095) goethite (FeOOH) (cod 2211652) sylvite (KCl) (cod 1000050) gibbsite (Al(OH)3) (cod 1200016) periclase (MgO) (cod 9006747) kaolinite (Al2Si2O5(OH)4) (cod 9009230) portlandite (Ca(OH)2) (cod 9000113)
The main minerals present in the IOTs and HCAs, and 880 cm-1 correspond to calcite (HORGNIES; as shown in Figure 1, were identified in the WILLIEME; GABET, 2011), and 1100 cm-1 diffractogram as showed in Table 5. corresponds to vibrations of Si–O bonds (PALOMO et al., 2007). The FTIR spectra of the industrial wastes are shown in Figure 2 and Figure 3. As shown in the As shown in Figure 4, most (i.e., 90 %) of the IOT IOTs, the band at 3650 cm-1 corresponds to and HCA samples had particles with diameters less kaolinite (DICK et al., 2008), the band at 3150 than 36.63 µm and 25.03 µm, respectively. The cm-1 corresponds to goethite (WECKLER; LUTZ, average particle diameters obtained in the test were 1998), the bands in the range of 800-1200 cm-1 14.13 µm for the tailings and 12.30 µm for the correspond to vibrations of Si–O bonds (DICK et ashes. al., 2008), and the band at 530 cm-1 corresponds The results of the compressive strength tests are to hematite (YANG et al., 2010). shown in Figure 5. The mortar with the higher For the HCAs, in Figure 3, the band at 3640 cm-1 compressive strength at 7 days was corresponds to portlandite (HORGNIES; HCA70IOT30SN1.85, but the result was quite WILLIEME; GABET, 2011), the bands at 1400 close for all mixtures with 1.85 and 1.55
Alkaline activation of high-calcium ash and iron ore tailings and their recycling potential in building materials 103 Ambiente Construído, Porto Alegre, v. 19, n. 3, p. 99-112, jul./set. 2019.
SiO2/Na2O ratios. At 28 days, there was an international documents regulating compressive increase in the strength, and the mixtures with 1.85 earth block masonry construction can be less and 1.55 ratios continued to have the best demanding. For instance, the New Zealand NZS performances. However, the mortar with a 1.00 4298 standard (STANDARDS…, 1998) requires a ratio showed better compressive strength with 30 minimum compressive strength of approximately % HCA and 70 % IOT. With an increase in the 1.52 MPa. The Spanish standard, UNE 41410 HCA content, the compressive strength of the (ASOCIACIÓN…, 2008), follows a similar trend mixture decreased. The compressive strength for since it requires that the lowest class provided this material is superior to that found by Silva et (BTC 1) delivers a normalized compressive al. (2015), who also utilized industrial waste and strength above 1.3 MPa. Thus, these mixtures can geopolymeric stabilization to make compressed also be used for the production of compressed blocks. The minimum value typically recognized blocks, contributing to valorization of non- for compressive earthen materials is 2 MPa at 28 hazardous waste and reducing its deposition days (HOUBEN; GUILLAUD, 2008). In fact, impact.
Figure 2 –FTIR of the IOTs
Figure 3 –FTIR of the HCAs
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Figure 4 – Diffractogram of (a) IOTs and (b) HCA
Figure 5 – Compressive strengths 6
5
4
3
2
1 Compressive strenght (MPa) 0 1.00 1.55 1.85 1.00 1.55 1.85 1.00 1.55 1.85 30-70 50-50 70-30 Ratio HCA-IOT 7 days 28 days
In addition to the geopolymerization, the amount similar for both 7 and 28 days, except for the of water present in each mixture contributed mixture of HCA/IOT at a ratio equal to 50/50 at 28 directly to the compressive strength. The trace with days. For the average compressive strength of the the highest water content (SiO2/Na2O = 1.00) was mixture at a SiO2/Na2O = 1.00 ratio, the other the one with the lowest strength. Thus, increasing admixture was not considered statistically similar, the water/activator ratio implies an increase in the without any exception. This could also be porosity of the mortar and a reduction in the supported by the largest amount of water in this compressive strength (WINNEFELD et al., 2010). mixture since this admixture has over 90 % and 125 % water than those with SiO2/Na2O = 1.55 and In the statistical analysis, the averages of the compressive strength tests for the mixtures with 1.85 ratios, respectively. However, that with the SiO2/Na2O ratios of 1.55 and 1.85 were considered
Alkaline activation of high-calcium ash and iron ore tailings and their recycling potential in building materials 105 Ambiente Construído, Porto Alegre, v. 19, n. 3, p. 99-112, jul./set. 2019.
SiO2/Na2O 1.55 ratio had only 18 % more water SiO2/Na2O ratios between 1.55 and 1.85, such than that with the 1.85 ratio. structures were smaller and more dispersed, as shown in Figure 10. Therefore, the absence of The FTIR spectra of the mortars show that there kaolinite in the mortars with a higher HCA content was a reaction between the industrial wastes, may be associated with the HCA reaction with resulting in the formation of new structures and calcium and thus the development of more consumption of others. According to Fig. 6, the resistant structures. Higher levels of calcium oxide mortars with the 1.00 SiO2/Na2O ratio maintained the bands for goethite and calcium carbonate, but result in a higher efficiency of kaolinite dissolution with lower Na2O/SiO2 ratios (WHITTINGTON, they have a lower intensity, and the wavenumber 1996). that is most expressive is at 1006 cm-1. That wavenumber corresponds to calcium Cube-like structures were found in mortars with aluminosilicate hydrates and aluminosilicates SiO2/Na2O ratios between 1.55 and 1.85, as shown (KAPELUSZNA et al., 2017), which provide in Figure 11. These structures can be linked to compressive resistance to the material. zeolite A because of its morphology (SILVA FILHO et al., 2015) and the increase in the In the case of the mortars with 1.55 and 1.85 mortars’ strength because they have been observed SiO2/Na2O ratios, shown in Figure 7 and 8, the same bands could be found: goethite (WECKLER; more clearly in formulations that have higher compressive strengths (AYELE et al., 2015). This LUTZ, 1998), calcium carbonate (HORGNIES; could also be confirmed by the FTIR spectra in WILLIEME; GABET, 2011) and calcium which mortars with the more expressive peaks for aluminosilicate hydrates and aluminosilicates aluminosilicates exhibited the best compression (DICK et al., 2008). However, the mixtures exhibited similar behaviors, which could explain strength values, except for mortars with a the more homogeneous mechanical performance. SiO2/Na2O, ratio = 1.00, which is due to the high amount of water that showed an unsatisfactory Morphologically, we observed higher IOT behavior for performance as a compressed block. percentages in the mortars and the occurrence of crystalline lamellar structures composed of It is important to highlight that these overlapping planes, as shown in Figure 9. This aluminosilicates structures were formed at room temperature. Tang, Guo and Wang (2013) structure can be associated with kaolinite because previously confirmed the interactions between of its morphology (SILVA FILHO et al., 2015). In kaolinite and calcium at room temperature, which higher HCA-content mortars, we found fewer produce crystalline aluminosilicates. kaolinite-like structures. For the mortars with
Figure 6 – FTIR spectra of the mortars with a 1.00 SiO2/Na2O ratio
106 Bezerra, A. C. S.; França, S.; Magalhães, L. F.; Carvalho, M. C. R. Ambiente Construído, Porto Alegre, v. 19, n. 3, p. 99-112, jul./set. 2019.
Figure 7 – FTIR spectra of the mortars with a 1.55 SiO2/Na2O ratio
Figure 8 – FTIR spectra of the mortars with a 1.85 SiO2/Na2O ratio
Alkaline activation of high-calcium ash and iron ore tailings and their recycling potential in building materials 107 Ambiente Construído, Porto Alegre, v. 19, n. 3, p. 99-112, jul./set. 2019.
Figure 9 – Kaolinite-like structure of the HCA30IOT70
Figure 10 – Micrographs of HCA50IOT50 (a) SN1.55, (b) SN1.85
(a) (b)
Figure 11 –Micrograph of the HCA70IOT30SN1.55 mortar
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Conclusion AMAYA, A. et al. Preparation of Charcoal Pellets from Eucalyptus Wood with Different Binders. This study investigated the potential of solid waste Journal of Energy and Natural Resources, v. 4, alkaline activators as a building material. The n. 2, p. 34, 2015. results showed that high-calcium ashes and iron AMERICAN SOCIETY FOR TESTING AND ore tailings are potential materials for the MATERIALS. C109/C109M-16a: standard test development of environmentally friendly building method for compressive strength of hydraulic materials. Moreover, when the solid industrial cement mortars (Using 2-in. or [50-mm] Cube wastes are reused, IOTs will no longer be disposed Specimens). West Conshohocken, 2016. of in the form of dams and no longer contaminate the soil or subsoil, which is safer for society and ASOCIACIÓN ESPAÑOLA DE the environment. HCAs will no longer be disposed NORMALIZACIÓN Y CERTIFICACIÓN. UNE of in landfills, avoiding possible soil pH changes, 41410: compressed earth blocks for walls: its leaching and loss of nutrients that can harm definitions, specifications and testing methods. agriculture. Through alkaline activation, the wastes Spain, 2008. could be stabilized without the use of cement, ASSOCIAÇÃO BRASILEIRA DE NORMAS which contributes to reducing the greenhouse TÉCNICAS. NBR 7215: cimento Portland: effect. determinação da resistência à compressão. Rio de Using alkaline activation, we observed the reaction Janeiro, 1996. between the industrial wastes. The FTIR spectra ASSOCIAÇÃO BRASILEIRA DE NORMAS showed that calcium aluminosilicate is the most TÉCNICAS. NBR7214: areia normal para ensaio expressive phase, which ensures the compressive de cimento: especificação. Rio de Janeiro, 2015. resistance of the material. Morphologically, the presence of kaolinite was identified as a AYELE, L. et al. Synthesis of Zeolite A From constituent of IOTs in the mortars. The kaolinite Ethiopian Kaolin. Microporous and Mesoporous may have reacted with the calcium from the ashes Materials, v. 215, p. 29-36, 2015. to form the calcium aluminosilicates. Zeolite A BASTOS, L. A. D. C. et al. Using Iron Ore was also observed and is an example of Tailings From Tailing Dams as Road material. aluminosilicate structures identified in the FTIR Journal of Materials in Civil Engineering, v. 28, spectra. n. 10, p. 04016102, 2016. Regarding the compressive strength, all BEZERRA, A. C. S. et al. Effect of Partial formulations except for that with a 1.00 SiO2/Na2O Replacement with Thermally Processed Sugar ratio have the potential for application in Cane Bagasse on the Properties of Mortars. compacted blocks since the minimum strength for Matéria, Rio de Janeiro, v. 22, n. 1, p. e11785, these blocks at 28 days is 2 MPa. Furthermore, 2017. other aspects need to be assessed in future investigations, such as the non-mechanical features CARRASCO, E. V. M et al. Characterization of of the masonry system. These include features, Mortars With Iron Ore Tailings Using Destructive such as the acoustic and thermal performance of and Nondestructive Tests. Construction and the masonry walls, the development and study of Building Materials, v. 131, p. 31-38, 2017. compatible renderings, and a durability CHATURVEDI, N.; AHMED, M. J.; DHAL, N. assessment. In addition, for the production of K. Effects of Iron ore Tailings on Growth and masonry elements, the use of two wastes without Physiological Activities of Tagetes Patula L. thermal processing and one of them originating Journal of soils and sediments, v. 14, n. 4, p. from biomass and having approximately 30 % of 721-730, 2014. carbon in its constitution will lead to the reduction CHOWDHURY, S.; MISHRA, M.; SUGANYA, of the carbon footprint of the constructions that use O. M. The Incorporation of Wood Waste Ash as a these elements. Partial Cement Replacement Material for Making Structural Grade Concrete: an overview. Ain References Shams Engineering Journal, v. 6, n. 2, p. 429- AIRES, U. R. V. et al. Changes in Land Use and 437, 2015. Land Cover as a Result of the Failure of a Mining Tailings Dam in Mariana, MG, Brazil. Land Use
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Augusto Cesar da Silva Bezerra Departamento de Engenharia de Transportes | Centro Federal de Educação Tecnológica de Minas Gerais | Av. Amazonas, 5253, Nova Suíssa | Belo Horizonte – MG – Brasil | CEP 30421-169 | Tel.: (31) 3319-7119 | E-mail: [email protected]
Sâmara França Departamento de Engenharia Civil | Centro Federal de Educação Tecnológica de Minas Gerais | Tel.: (31) 3319-6848 | E-mail: [email protected]
Luciano Fernandes de Magalhães Departamento de Engenharia de Materiais | Centro Federal de Educação Tecnológica de Minas Gerais | Tel.: (31) 3319-7155 | E-mail: [email protected]
Maria Cristina Ramos de Carvalho Departamento de Engenharia Civil | Centro Federal de Educação Tecnológica de Minas Gerais | Tel.: (31) 33196848 | E-mail: [email protected]
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112 Bezerra, A. C. S.; França, S.; Magalhães, L. F.; Carvalho, M. C. R.